An arrangement of this kind is known, for example, from EP 0 235 683 B1. In this known arrangement, the swivel frame, in the region of its front and rear end, is provided with sliding stones which in pairs engage an associated curved slot of a front and rear stationary end shield which is integrated into the machine frame. Such end shields, at their bottom rim which is concentric to the curved slot, are provided with gear teeth which are in engagement with a pinion that can be driven by a handwheel. The pinion shaft associated with the pinions and accommodating the handwheel is mounted on the swivel frame and projects from the machine frame requiring, for that purpose, a reach-through slot which is arranged in concentric position to the curved slot of the stationary end shields.
The disadvantage, however, of such an arrangement lies in the fact that the pinion shaft carries out all swivel movements of the swivel frame, so that the handwheel accommodated on the pinion shaft changes its position during each swivel movement of the swivel frame. This constitutes an undesirable effect with regard to operation. Furthermore, the reach-through slot of the machine frame, through which the pinion shaft extends may constitute a safety risk and has to be guarded accordingly. The direct transmission of the rotary movement of the handwheel to the swivel frame has an unfavourable effect also with regard to the obtainable degree of accuracy. Furthermore, in the known arrangement the swivel frame suspended in the machine frame is separated from the table board, rendering assembly difficult.
On the basis of the foregoing, it is thus the object of the present invention to improve a device as described initially above by using simple and low-cost means, so that not only a high degree of user-friendliness, safety and accuracy, but also a clear-cut design are achieved.